Calcium-based desulfurizer, preparation method thereof and application of calcium-based desulfurizer in high-concentration carbon dioxide flue gas

Abstract

The invention belongs to the technical field of desulfurizer preparation and flue gas purification treatment, and particularly relates to a calcium-based desulfurizer, a preparation method thereof and application of the calcium-based desulfurizer in high-concentration carbon dioxide flue gas. The preparation method of the calcium-based desulfurizing agent comprises the following steps: mixing quick lime, a first modifier, a second modifier and water, performing digestion reaction in a reactor, and drying the obtained reaction mixture to obtain the calcium-based desulfurizing agent, the first modifier is N-acyl amino acid salt formed by amino acid and derivatives thereof and C8-C18 alkyl chains through amido bonds; the second modifier is an alkyl glycoside compound. The key point of the invention is that two specific modifiers, namely N-acylamino acid salt and alkyl glycoside compounds, are introduced in the process of preparing calcium hydroxide by adopting a digestion process, so that the prepared calcium-based desulfurizing agent has high desulfurization efficiency in desulfurization treatment of flue gas containing high-concentration carbon dioxide.

Description

Technical Field

[0001] This invention belongs to the field of desulfurizing agent preparation and flue gas purification technology, specifically relating to a calcium-based desulfurizing agent, its preparation method, and its application in high-concentration carbon dioxide flue gas. Background Technology

[0002] Commonly used methods for reducing SO2 emissions from industrial flue gas include wet desulfurization, semi-dry desulfurization, and dry desulfurization. Dry desulfurization, with its advantages of high efficiency, fewer desulfurization units, stable operation, and low energy consumption, is widely used in flue gas purification processes for lower sulfur dioxide concentrations. However, traditional dry desulfurizing agents, such as sodium bicarbonate, suffer from high operating costs and difficulties in the standardized disposal of sodium-based desulfurization byproducts. Calcium-based desulfurizing agents (calcium hydroxide, also known as slaked lime) are widely used due to their inexpensive and readily available raw materials, alkalinity, wide applicable temperature range, and relatively inert and easily treatable byproducts. However, they suffer from low calcium utilization, low desulfurization efficiency leading to high dosage consumption, and inability to cope with conditions with large fluctuations in SO2 concentration, such as in the cement industry, thus failing to meet SO2 emission requirements.

[0003] Current domestic and international efforts to address the aforementioned problems with calcium-based desulfurizers aim to enhance their reactivity by reducing the particle size of slaked lime and increasing its specific surface area and porosity, thereby improving desulfurization efficiency. However, the CO2 concentration in flue gas from different industries and boilers varies significantly. For example, the CO2 concentration in flue gas from the power industry is approximately 8-15%, while the flue gas from cement kilns is characterized by high CO2 concentrations, typically ranging from 15-25%, or even exceeding 30%. CO2 competes with SO2, occupying active sites in the desulfurizer. Simultaneously, the calcium carbonate formed by the reaction of CO2 and the desulfurizer blocks reaction channels, leading to high consumption of slaked lime desulfurizer. Therefore, even increasing the specific surface area of ​​slaked lime in dry desulfurization processes has limited effect on improving desulfurization efficiency for high CO2 concentration flue gas. Thus, designing a calcium-based desulfurizer suitable for high CO2 concentration flue gas desulfurization to achieve highly efficient desulfurization is of paramount importance. Summary of the Invention

[0004] One of the objectives of this invention is to address the problem of poor desulfurization effect of existing calcium hydroxide desulfurizers in high-concentration carbon dioxide flue gas, and to provide a method for preparing a calcium-based desulfurizer. The calcium-based desulfurizer prepared by this method exhibits significantly improved desulfurization efficiency in the desulfurization treatment of high-concentration carbon dioxide flue gas.

[0005] Specifically, the preparation method of the calcium-based desulfurizer includes the following steps: quicklime, a first modifier, a second modifier, and water are mixed and digested in a reactor. The resulting reaction mixture is dried to obtain the calcium-based desulfurizer. The first modifier is an N-acyl amino acid salt formed by amino acids and their derivatives with C8~C18 alkyl chains through amide bonds. The second modifier is an alkyl glycoside compound.

[0006] In a preferred embodiment, with the amount of quicklime being 500 parts by weight, the amount of the first modifier is 0.65 to 6.5 parts by weight, the amount of the second modifier is 0.65 to 13.0 parts by weight, and the amount of water is 200 to 350 parts by weight.

[0007] In a preferred embodiment, the mass ratio of the first modifier to the second modifier is 1:(0.5~5).

[0008] In a preferred embodiment, the quicklime contains 85 wt% or more of CaO.

[0009] In a preferred embodiment, the activity of the quicklime is 280 mL or more.

[0010] In a preferred embodiment, the quicklime has a 200-mesh sieve pass rate of over 90%.

[0011] In a preferred embodiment, the amino acid and its derivatives are selected from at least one of sarcosine, glutamic acid, aspartic acid, glycine, alanine, lysine, and arginine.

[0012] In a preferred embodiment, the first modifier is selected from at least one of the following N-acyl amino acid salts: sodium N-lauroyl sarcosinate, sodium N-lauroyl glutamate, sodium N-myristoyl sarcosinate, sodium N-cocoyl glutamate, sodium N-lauroyl aspartate, sodium N-myristoyl aspartate, sodium N-stearoyl glutamate, sodium N-palmitoyl glutamate, sodium N-lauroyl glycinate, and sodium N-lauroyl alanine.

[0013] In a preferred embodiment, the second modifier is selected from at least one of octyl glucoside, decyl glucoside, cocoyl glucoside, and lauryl glucoside.

[0014] In a preferred embodiment, the digestion reaction is carried out under stirring conditions, with a stirring speed of 300 r / min or higher and a time of 3 to 6 min.

[0015] In a preferred embodiment, the stirring speed is 300~500 r / min.

[0016] In a preferred embodiment, the drying temperature is 100~150°C.

[0017] In a preferred embodiment, the calcium-based desulfurizing agent has a water content of less than 2 wt% and a surface area of ​​28-50 m². 2 / g.

[0018] The second objective of this invention is to provide a calcium-based desulfurizer prepared by the above method.

[0019] A third objective of this invention is to provide the application of the calcium-based desulfurizer in high-concentration carbon dioxide flue gas.

[0020] In a preferred embodiment, the concentration of carbon dioxide in the flue gas is 10-30%.

[0021] Beneficial Effects: The key to this invention lies in introducing two specific modifiers, N-acyl amino acid salts and alkyl glycosides, during the digestion process to prepare calcium hydroxide. The resulting calcium-based desulfurizer exhibits high desulfurization efficiency in the desulfurization treatment of flue gas containing high concentrations of carbon dioxide. The reason for this is speculated to be twofold: Firstly, the carboxyl group of the N-acyl amino acid salt adsorbs onto specific crystal faces of Ca(OH)₂ crystals through ionic bonds or strong electrostatic interactions, inhibiting crystal growth and forming smaller, more irregular Ca(OH)₂ particles. The polyhydroxy structure of the alkyl glycosides forms a dense hydrogen bond network with the amino acid head groups of the N-acyl amino acid salt, further preventing the aggregation of Ca(OH)₂ particles, thus playing a "stereodispersive" role. This increases and maintains the high specific surface area of ​​Ca(OH)₂, providing more and more accessible active sites and gas diffusion channels for the desulfurization reaction, thereby improving the sulfur dioxide removal efficiency. Secondly, through the synergistic effect of the N-acyl amino acid salt and alkyl glycosides on Ca(OH)₂… A highly polar interfacial "shell" rich in hydroxyl groups is constructed on the surface of Ca(OH)2. At this time, polar SO2 molecules are more likely to dissolve and diffuse through the polar "shell" to react with Ca(OH)2. At the same time, this "shell" effectively reduces the contact and reaction between nonpolar CO2 molecules and the active sites of the desulfurizer, enabling the Ca(OH)2 desulfurizer to efficiently and specifically remove polar SO2 molecules from flue gas, thereby improving the sulfur dioxide removal efficiency of the desulfurizer in high-concentration carbon dioxide flue gas. In addition, N-acyl amino acid salts and alkyl glycosides can also maintain the stability of their performance and structure in the strongly alkaline environment of the digestion reaction, thus stably constructing the aforementioned highly polar interfacial "shell" rich in hydroxyl groups on the surface of Ca(OH)2. In summary, this invention significantly improves the desulfurization efficiency of the obtained calcium-based desulfurizer in the desulfurization treatment of high-concentration carbon dioxide flue gas by introducing two specific modifiers: N-acyl amino acid salts and alkyl glycosides. Furthermore, this calcium-based desulfurizer has a high specific surface area and pore volume, enabling it to adapt well to SO2 concentration fluctuations under different flue gas conditions. The high desulfurization efficiency also helps reduce dosage consumption and lower desulfurization costs. The preparation method is simple and environmentally friendly, and the raw materials involved are inexpensive and readily available, resulting in good environmental and economic benefits. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Furthermore, unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.

[0023] The method for preparing the calcium-based desulfurizer provided by the present invention includes the following steps: quicklime, a first modifier, a second modifier, and water are mixed and digested in a reactor, and the resulting reaction mixture is dried to obtain the calcium-based desulfurizer; the first modifier is an N-acyl amino acid salt formed by amino acids and their derivatives and C8~C18 alkyl chains through amide bonds; the second modifier is an alkyl glycoside compound.

[0024] In this invention, the C8-C18 alkyl chain can be represented by *-R, where R represents a C8-C18 alkyl group, such as octyl, nonyl, decyl, undecyl, lauryl, myristyl, palmityl, stearyl, etc., and * indicates the position where it is attached to the C in the amide bond (-CO-N(R`)-), where N(R`) in the amide bond (-CO-N(R`)-) comes from amino acids and their derivatives. The alkyl glycoside compound refers to a compound obtained by the loss of one molecule of water from the hemiacetal hydroxyl group of a sugar and the hydroxyl group of a fatty alcohol under acid catalysis, wherein the sugar can be a monosaccharide or a disaccharide.

[0025] In this invention, the reactor can be any conventional digestion reactor suitable for industrial production, such as a primary digester or a tertiary digester.

[0026] In this invention, with the amount of quicklime used being 500 parts by weight, the amount of the first modifier is preferably 0.65 to 6.5 parts by weight, such as 0.65, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 6.5 parts by weight or any value between them; the amount of the second modifier is preferably 0.65 to 13.0 parts by weight, such as 0.65, 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 13.0 parts by weight or any value between them; the amount of water is preferably 200 to 350 parts by weight, such as 200, 220, 250, 280, 300, 320, 350 parts by weight or any value between them. When the ratio of quicklime to the first modifier and the second modifier is controlled within the above-mentioned preferred range, it is more conducive to the effective and relatively uniform adsorption of the modifier on the surface of calcium hydroxide particles, thereby increasing the specific surface area of ​​the desulfurizer and constructing a high-polarity interface layer. At the same time, it avoids pore blockage and reduced product economy due to excessive addition.

[0027] In this invention, the preferred mass ratio of the first modifier to the second modifier is 1:(0.5~5), such as 1:0.5, 1:0.8, 1:1, 1:2, 1:3, 1:4, 1:5, or any ratio between them. This is more conducive to forming a structurally stable and functionally complete composite modified layer on the surface of the calcium-based desulfurizer, that is, constructing a highly polar interfacial "shell" rich in hydroxyl groups on the Ca(OH)2 surface. This significantly increases the specific surface area and reaction diffusion channels of Ca(OH)2 particles through dispersion, and enhances the surface's targeted adsorption and removal capacity for SO2 through synergistic polarity. It also helps to avoid the problems of decreased thermal and chemical stability of the composite modified layer due to insufficient addition of the first modifier, and reduced SO2 targeting selectivity due to an excessively thin interfacial "shell" caused by insufficient addition of the second modifier.

[0028] In this invention, the CaO content in the quicklime is preferably 85 wt% or more, such as 85 wt%, 88 wt%, 90 wt%, 92 wt%, 95 wt%, 98 wt%, etc., more preferably 85-95 wt%. The activity of the quicklime is preferably 280 mL or more, such as 280 mL, 300 mL, 320 mL, 350 mL, etc. The 200-mesh sieve pass rate of the quicklime is preferably 90% or more, at which point the quicklime powder is finer and has better reactivity.

[0029] In this invention, specific examples of the amino acids and their derivatives include, but are not limited to, at least one of sarcosine, glutamic acid, aspartic acid, glycine, alanine, lysine, and arginine.

[0030] In this invention, specific examples of the first modifier include, but are not limited to, the N-acyl amino acid salt being at least one of N-lauroyl sarcosinate sodium, N-lauroyl glutamate sodium, N-myristoyl sarcosinate sodium, N-cocoyl glutamate sodium, N-lauroyl aspartate sodium, N-myristoyl aspartate sodium, N-stearoyl glutamate sodium, N-palmitoyl glutamate sodium, N-lauroyl glycinate sodium, and N-lauroyl alanine sodium.

[0031] In this invention, specific examples of the second modifier include, but are not limited to, at least one selected from octyl glucoside, decyl glucoside, cocoyl glucoside, and lauryl glucoside.

[0032] In this invention, the digestion reaction is preferably carried out under stirring conditions. The stirring speed is preferably 300 r / min or higher, such as 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, etc., more preferably 300~500 r / min; the stirring time is preferably 3~6 min, such as 3 min, 4 min, 5 min, 6 min or any value between them.

[0033] In this invention, the drying temperature is preferably 100~150℃, such as 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, or any value between them. This invention does not impose any particular limitation on the drying time, as long as the moisture content of the calcium-based desulfurizer can be reduced to below 2wt%.

[0034] In this invention, the water content of the calcium-based desulfurizing agent is preferably below 2 wt%, at which point the calcium-based desulfurizing agent exhibits better flowability and storage performance. The surface area of ​​the calcium-based desulfurizing agent is preferably 28-50 m². 2 / g, such as 28m 2 / g、30m 2 / g、32m 2 / g、35m 2 / g、38m 2 / g、40m 2 / g、42m 2 / g、45m 2 / g、48m 2 / g, 50m 2 / g or any value between them. This is more conducive to providing more reactive sites and gas diffusion channels for the desulfurization reaction, thereby improving the desulfurization reaction efficiency and calcium utilization.

[0035] This invention also provides the application of the calcium-based desulfurizer prepared by the above method in high-concentration carbon dioxide flue gas. Further, the concentration of carbon dioxide in the flue gas is preferably 10% or more, more preferably 10-35%, such as 10%, 15%, 20%, 25%, 30%, 35%, or any value between them. The specific source of the flue gas is not particularly limited, and it can be any one or more of cement kiln flue gas, lime kiln flue gas, blast furnace gas, coal-fired power plant flue gas, and gas-fired power plant flue gas.

[0036] Furthermore, the calcium-based desulfurizer prepared using the method provided in this invention exhibits high desulfurization efficiency even in low-concentration carbon dioxide flue gas (carbon dioxide concentration ≤10%). Under the same flue gas conditions, compared to other existing calcium-based desulfurizers, the calcium-based desulfurizer of this invention has higher desulfurization efficiency, requires less dosage, and has lower desulfurization costs.

[0037] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0038] The quicklime used in the following examples and comparative examples all had a CaO content of 85%, an activity of 350 mL, and a 200-mesh sieve pass rate of over 90%.

[0039] Example 1 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 3.5 parts by weight of N-lauroyl sarcosine sodium and 3.5 parts by weight of octyl glucoside were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.0 wt%, thus obtaining the calcium-based desulfurizer.

[0040] Example 2 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 0.65 parts by weight of N-lauroyl sarcosinate sodium and 3.25 parts by weight of octyl glucoside were dissolved in 350 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 500 r / min for 4 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 0.8 wt%, thus obtaining the calcium-based desulfurizer.

[0041] Example 3 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 6.5 parts by weight of N-lauroyl sarcosinate sodium and 13 parts by weight of octyl glucoside were dissolved in 300 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 300 r / min for 6 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.1 wt%, thus obtaining the calcium-based desulfurizer.

[0042] Example 4 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 3.5 parts by weight of sodium N-cocoyl glutamate and 3.5 parts by weight of decyl glucoside were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.0 wt%, thus obtaining the calcium-based desulfurizer.

[0043] Example 5 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 3.5 parts by weight of N-myristoyl aspartate sodium and 3.5 parts by weight of lauryl glucoside were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 0.9 wt%, thus obtaining the calcium-based desulfurizer.

[0044] Example 6 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 6.5 parts by weight of N-lauroyl sarcosine sodium and 0.65 parts by weight of octyl glucoside were dissolved in 350 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.2 wt%, thus obtaining the calcium-based desulfurizer.

[0045] Example 7 This embodiment illustrates the preparation of a calcium-based desulfurizing agent, and the specific process is as follows: In a digestion reactor, 0.65 parts by weight of N-lauroyl sarcosine sodium and 13 parts by weight of octyl glucoside were dissolved in 300 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.2 wt%, thus obtaining the calcium-based desulfurizer.

[0046] Comparative Example 1 This comparative example illustrates the preparation of a reference calcium-based desulfurizer, and the specific process is as follows: In a digestion reactor, 7 parts by weight of N-lauroyl sarcosine sodium were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.1 wt%, thus obtaining the reference calcium-based desulfurizer.

[0047] Comparative Example 2 This comparative example illustrates the preparation of a reference calcium-based desulfurizer, and the specific process is as follows: In a digestion reactor, 7 parts by weight of octyl glucoside were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 0.9 wt%, thus obtaining the reference calcium-based desulfurizer.

[0048] Comparative Example 3 This comparative example illustrates the preparation of a reference calcium-based desulfurizer, and the specific process is as follows: In a digestion reactor, 7 parts by weight of triethanolamine were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.2 wt%, thus obtaining the reference calcium-based desulfurizer.

[0049] Comparative Example 4 This comparative example illustrates the preparation of a reference calcium-based desulfurizer, and the specific process is as follows: In a digestion reactor, 7 parts by weight of sodium dodecylbenzenesulfonate were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.2 wt%, thus obtaining the reference calcium-based desulfurizer.

[0050] Comparative Example 5 This comparative example illustrates the preparation of a reference calcium-based desulfurizer, and the specific process is as follows: In a digestion reactor, 3.5 parts by weight of sodium N-myristoyl aspartate and 3.5 parts by weight of sodium dodecylbenzenesulfonate were dissolved in 250 parts by weight of water to prepare a digestion solution. After adding 500 parts by weight of quicklime, the digestion reaction was carried out under stirring at a speed of 400 r / min for 5 min. The resulting reaction mixture was then heated to 120°C and dried until the water content was 1.2 wt%, thus obtaining the reference calcium-based desulfurizer.

[0051] Test case (1) The calcium-based absorbents prepared in the above examples and comparative examples were subjected to N2 adsorption-desorption curve tests, and the specific surface area data obtained are shown in Table 1.

[0052] (2) The desulfurization effect of the calcium-based desulfurizers obtained in the above examples and comparative examples was tested using a fixed-bed reactor under simulated cement kiln flue gas conditions. The specific test steps and parameter conditions are as follows: 1g of calcium-based desulfurizer was loaded into the fixed-bed reactor. The system was first introduced with 4L / min N2. After the reactor temperature was raised to 180℃, simulated cement kiln flue gas was introduced with the following parameters: SO2 concentration was 70ppm, NO concentration was 373ppm, O2 was 10vol%, CO2 was 20vol%, H2O was 10vol%. N2 was used as the balance gas, and the total flow rate of the mixed gas was controlled at 4L / min. The SO2 concentration of the outlet gas was analyzed online using the CEMS-2000M continuous emission monitoring system, and the concentration was determined according to formula (1): η(%)=(SO 2(in) -SO 2(out) ) / SO 2(in) *100, where η is the desulfurization efficiency under this operating condition, "in" is the inlet volume fraction (ppm) of the substance, and "out" is the outlet volume fraction (ppm) of the substance. The desulfurization efficiency is calculated. The results are shown in Table 1.

[0053] Table 1

[0054] As shown in Table 1, compared with the comparative examples, the calcium-based desulfurizers prepared in Examples 1-7 of this invention exhibit higher desulfurization efficiency in simulated high-concentration CO2 flue gas.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for preparing a calcium-based desulfurizing agent, characterized in that, The preparation method includes the following steps: quicklime, a first modifier, a second modifier, and water are mixed and digested in a reactor. The resulting reaction mixture is dried to obtain the calcium-based desulfurizer. The first modifier is an N-acyl amino acid salt formed by amino acids and their derivatives with C8~C18 alkyl chains through amide bonds. The second modifier is an alkyl glycoside compound.

2. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, When the amount of quicklime used is 500 parts by weight, the amount of the first modifier is 0.65 to 6.5 parts by weight, the amount of the second modifier is 0.65 to 13 parts by weight, and the amount of water is 200 to 350 parts by weight. Preferably, the mass ratio of the first modifier to the second modifier is 1:(0.5~5).

3. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, The quicklime contains more than 85 wt% CaO; Preferably, the activity of the quicklime is 280 mL or more; Preferably, the quicklime has a 200-mesh sieve pass rate of over 90%.

4. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, The amino acids and their derivatives are selected from at least one of sarcosine, glutamic acid, aspartic acid, glycine, alanine, lysine, and arginine. Preferably, the first modifier is selected from at least one of the following N-acyl amino acid salts: sodium N-lauroyl sarcosinate, sodium N-lauroyl glutamate, sodium N-myristoyl sarcosinate, sodium N-cocoyl glutamate, sodium N-lauroyl aspartate, sodium N-myristoyl aspartate, sodium N-stearoyl glutamate, sodium N-palmitoyl glutamate, sodium N-lauroyl glycinate, and sodium N-lauroyl alanine. Preferably, the second modifier is selected from at least one of octyl glucoside, decyl glucoside, cocoyl glucoside, and lauryl glucoside.

5. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, The digestion reaction is carried out under stirring conditions, with a stirring speed of 300 r / min or higher and a time of 3 to 6 min; Preferably, the stirring speed is 300~500 r / min.

6. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, The drying process is carried out at a temperature of 100~150℃.

7. The method for preparing the calcium-based desulfurizing agent according to claim 1, characterized in that, The calcium-based desulfurizing agent has a water content of less than 2 wt% and a specific surface area of ​​28-50 m². 2 / g.

8. A calcium-based desulfurizer prepared by the method according to any one of claims 1 to 7.

9. The application of the calcium-based desulfurizer according to claim 8 in high-concentration carbon dioxide flue gas.

10. The application of the calcium-based desulfurizer according to claim 9 in high-concentration carbon dioxide flue gas, characterized in that, The concentration of carbon dioxide in the flue gas is above 10%.

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